Close asteroid fly-by will help test planetary defence capabilities

31st July 201712:59 pm31st July 20171:00 pm

NASA and JPL expect close approach of asteroid 2012 TC4 will assist in testing worldwide detection and tracking network

The asteroid, which is between 10 and 30m across, will fly close to the Earth on 12th October. Although NASA’s astronomers are certain it will not hit the planet — unlike the slightly smaller rock that burned up in the atmosphere over Chelyabinsk in Russia in 2013 — they do not yet know exactly how close the body’s orbit will bring it to us; their only certainty is that the distance will be between 6800km and 270,000km from Earth’s surface.

Usually, close asteroid approaches such as this are used to gather data to characterise them, but in this case researchers at NASA and the Jet Propulsion Laboratory will also test the equipment and procedures that would be used in case of an unexpected and potentially catastrophic heavenly body encounter.

Asteroid 2012 TC4 to scale

“This is the perfect target for such an exercise because while we know the orbit of 2012 TC4 well enough to be absolutely certain it will not impact Earth, we haven’t established its exact path just yet,” said Paul Chodas, manager of the Center for Near-Earth Object Studies (CNEOS) at JPL. “It will be incumbent upon the observatories to get a fix on the asteroid as it approaches, and work together to obtain follow-up observations than make more refined asteroid orbit determinations possible.”

2012 TC4 was first discovered on 5 October 2012 by the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) from Haleakala on the island of Maui, Hawaii, when it passed around 96,000km from the Earth — about a quarter of the distance to the Moon. The telescope tracked the object’s trajectory for seven days, and all predictions about its future movements are derived from those observations. 2012 TC4 has not been seen since, there has been no opportunity to refine the predictions of its trajectory.

“We are using this asteroid flyby to test the worldwide asteroid detection and tracking network, assessing our capability to work together in response to finding a potential real asteroid threat,” said Michael Kelley, program scientist and NASA Headquarters lead for the TC4 observation campaign.

The effort involves a dozen observatories, labs and universities around the world, explains Vishnu Reddy of University of Arizona’s Lunar and Planetary Laboratory in Tucson, who leads the campaign to reacquire 2012 TC4.

“This effort will exercise the entire system, to include the initial and follow-up observations, precise orbit determination, and international communications.” Chodas added.

How far in front of the Statue of Liberty is the asteroid? Since the asteroid is supposed to be no more than 30m long/high, and the Statue of Liberty is 34m from the heel to the top of the head, the image surely doesn’t have them side by side.

There seems a Hugh disparity between the min/max distances from close earth mentioned. This despite the fact it was discovered and tracked in detail in 2012. I find it a little worrisome, we still have no real fix on the asteroid which will arrive in less than 3 months time and which was as close as one quarter distance to the moon in 2012.

At what min distance is the defence system activated? And is it a simple blasting out of the sky system? And how is the resulting wide spread rock shower controlled?
Can someone enlighten me lease?? Thanks Michael

Hi Michel
NASA have this on their website –
The key to preventing an impact is to find any potential threat as early as possible. With a couple of decades of warning, which would be possible for 100-meter-sized asteroids with a more capable detection network, several options are technically feasible for preventing an asteroid impact.

Deflecting an asteroid that is on an impact course with Earth requires changing the velocity of the object by less than an inch per second years in advance of the predicted impact. The two most promising techniques that NASA is investigating are the kinetic impactor (hitting an asteroid with an object to slightly slow it down) and the gravity tractor (gravitationally tugging on an asteroid by station-keeping a large mass near it).

Asteroids of different size are detectable at different distances and need different energies, to be deflected strong enough, to miss the earth, or be disintegrated.
When you consider, that the mass and therefore kinetic energy and momentum (at a given speed) goes with the 3rd power of length and cross section meaning visibility only with the square, larger objects, while easier to detect, pose a harder challenge to neutralize. Particularly, if we have exactly 1 attempt.
There is some literature available on how to influence asteroids.
There is of course a lower bound to size, where you can simply ignore it,
and there is an upper bound, where its visibility is high enough, to detect
it anywhere in it’s solar orbit, if it’s similar to the earth orbit, which is true
for the vast majority of “near earth objects”, that have a high chance for many
close encounters.
The most unfortunate encounter would be with a sufficiently large object
on a highly elliptical orbit or from outer space, since it’s very fast and comes from a direction, the survey programs don’t look at, since they are very rare.

Michael Bradley
How far in front of the Statue of Liberty is the asteroid? Since the asteroid is supposed to be no more than 30m long/high, and the Statue of Liberty is 34m from the heel to the top of the head, the image surely doesn’t have them side by side.

Agreed, why not put it next to a UK double-decker bus, that seems to be the standard when judging is required, dinosaours, etc. Statue of Liberty?

Agreed, why not put it next to a UK double-decker bus, that seems to be the standard when judging is required, dinosaours, etc. Statue of Liberty?

Because they would have to pay the congestion charge if they took the asteroid into London to photograph it next to a London bus and they would also either have to keep moving the asteroid alongside a moving bus, or wait until a bus stopped. The Statue of Liberty doesn’t move……. or does it?.